Device in heat exchanger



Patented Dec. 1, 1953 UNITED STATES ATENT OFFICE DEVICE IN HEAT EXCHANGER Application September 15, 1949, Serial No. 115,840

Claims priority, application Sweden September 16, 1948 This invention relates to radiation heat exchangers in which a gaseous heat source is introduced through a refractory nozzle or inlet into a heat exchanging chamber containing a set of gas tubes attached to a header disposed just outside said nozzle.

In running such heat exchangers with extremely hot gases of, for instance, a temperature of about 1400 C. serious attacks were met with on said header and difliculties were encountered in designing the means for carrying said nozzle. It is an object of the invention to provide means for preventing such attacks and difficulties without interfering with the favourable positioning of the tubes and header relative to the inlet of the heating gas or resorting to the use of insulating material. It is also an object of the invention to make feasible the ready control of the temperature conditions at the header without interfering with the efficiency of the heat source.

To obtain these and other valuable objects a cooling jacket is arranged between the nozzle and the header, preferably leaving a space between the jacket and the header to be filled up by the gaseous medium of the heat exchanging chamber so that the header is not unduly cooled. In case of using gaseous cooling medium in the jacket, it is possible by the present invention simultaneously to recover heat carried away by the cooling medium, for instance, by cooling with air or gaseous fuel to be used for the combustion for forming the heat source, or with the gas to be heated in the tubes which is thus preheated.

An embodiment of the invention will now be described with reference to the attached drawing showing in section the top portion of a radiation heat exchanger having an inlet nozzle and header as well as a cooling jacket according to the invention. It should, however, be noted that the invention is not limited to the embodiment illustrated.

At the bottom of the illustration the upper portion I of the brick work of a tube shaft is shown carrying the distribution or collection header 2 for the gas to be heated. A bundle of a plurality of tubes 3 is suspended from said header. The nozzle consists of a refractory inner portion A forming the walls of the nozzle and an outer insulating portion 5 and has at the top an inlet portion 6 for the heat source which is introduced through the opening 1.

Between the header 2 and the inner portion 4 of the nozzle there is an interspace ID in which a cooling jacket I I is placed so as to embrace the inner parts of the nozzle. As shown in the draw- 8 Claims. (Cl. 263-44 ing, the interspace I0 is open at the bottom and communicates with the heat exchange chamber formed by the shaft I. The cooling jacket H is secured to the angle iron [3 which in turn rests on the U-shaped bar [4. The jacket has an angularly shaped cross-section, an inwardly projecting portion l2 extending below the peripherally outer parts of the wall 4 of the nozzle. As illustrated in the drawing the innermost portion of the Wall 4 projects over the jacket portion IE to protect the latter from radiation. The extension l2 of the jacket enters consequently into a recess in the nozzle wall l. By properly shaping the extension 12 and the recess the nozzle wall 4 can with advantage be carried by the jacket.

The cooling jacket is connected to a number of inlet and outlet pipes l5 and It, respectively, for the cooling medium. The inlet pipes open near the bottom of the jacket [2 through openings l7, and the outlet pipes are connected with the jacket over openings 18 in the upper portion of the side of the jacket. The cooling medium is supplied to the jacket through an annular inlet tube 20 which is fed through the connection piece 2! and is connected to the inlet pipes 15 of the cooling jacket by means of curved pipes 19. From the outlet pipes [6 the cooling medium passes through the curved pipes 22 to an annular outlet tube 23 and leaves through the connection piece 24.

In the embodiment shown in the drawing the inlet and outlet pipes are evenly distributed along the cooling jackets and the pipes alternate so that every second pipe is an inlet and every second an outlet pipe. These details and the arrangement of the annular inlet and outlet tubes may, of course, be carried out in any adequate way to suit special purposes.

By reason of the fact that the inlet and outlet openings in the cooling jacket proper are placed in the bottom and top portion thereof, respectively, an eifective circulation of the cooling medium and consequently a good cooling is obtained. The cooling medium heated in the system may of course be used later for some other useful purpose. If for instance air is used it can, as stated above, be passed to the combustion zone of the gas heater after having served as cooling medium and been preheated thereby.

What is claimed is:

1. A heat exchanger comprising a vertical wall forming a heat exchange chamber, .a refractory wall extending vertically above the top of said chamber forming a nozzle coaxial with said 3. chamber for supplying heating gas thereto and directly exposed to the heating gas, a header for gaseous medium to be heated surrounding the lower end portion of said refractory wall, a plurality of tubes in said chamber connected to said header, a cooling jacket also surrounding a portion of said refractory wall adjacent the lower end thereof and on which said refractory wall is supported, said jacket having inlet and outlet connections thereto for a cooling medium.

2. A heat exchanger as claimed in claim 1, in which said jacket has a plurality of inlets distributed along its length and a plurality of outlets alternating with said inlets.

3. A heat exchanger as claimed in claim 1, in which the vertical wall forming said exchange chamber includes a shoulder at the top thereof, said tubes being attached to said header near its innermost wall, the portion of the bottom of said header outside said tubes resting on said shoulder.

4. A heat exchanger as claimed in claim 1, in which said inlet and outlet connections for the cooling medium are positioned outside said heat exchange chamber.

5. In a heat exchanger, the combination of a vertical wall forming a heat exchange chamber, a refractory wall at the top of said chamber forming an inlet for a heating medium coaxial with said chamber and directly exposed to the heating medium, an annular header for the fluid to be heated surrounding a portion of said refractory wall, a plurality of tubes in said chamber connected to said. header, and means for supporting said refractory wall including an annular cooling jacket in substantially the same horizontal plane as said header intermediate the latter and said refractory wall.

6. A heat exchanger as claimed in claim 5, in which said jacket includes an inwardly-pro- 4 jecting portion on which said refractory wall is supported.

7. A heat exchanger comprising a vertical shaft forming a heat exchange chamber, a nozzle at the top of said chamber forming an inlet thereto for heating gas, said nozzle including an inner wall of refractory material directly exposed to the heating gas, an annular header for the medium to be heated supported by said shaft at the upper end of said chamber and surrounding a portion of the refractory wall of said nozzle, a plurality of tubes in said chamber connected to said header, and means for supporting said nozzle including an annular cooling jacket also surrounding a portion of said refractory wall adjacent said header and on which said wall is supported.

8. A heat exchanger as claimed in claim 7, in which said cooling jacket is interposed between said header and said refractory wall and is angularly shaped in cross section to provide a horizontally extending portion on which said wall is supported.

KJELL PER ARN'E OHLANDER.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain Mar. 15, 1917 Number Number 

